Factor out common resource create/initialize/set-finalizer cycle

1 files changed, 27 insertions, 0 deletions

diff --git a/src/Foreign/Ptr/CreateWithFinalizer.hs b/src/Foreign/Ptr/CreateWithFinalizer.hs
new file mode 100644
index 0000000..b1dd583
--- /dev/null
+++ b/src/Foreign/Ptr/CreateWithFinalizer.hs
@@ -0,0 +1,27 @@
+-- Copyright 2018 Google LLC
+--
+-- Licensed under the Apache License, Version 2.0 (the "License"); you may not
+-- use this file except in compliance with the License. You may obtain a copy of
+-- the License at
+--
+--     https://www.apache.org/licenses/LICENSE-2.0
+--
+-- Unless required by applicable law or agreed to in writing, software
+-- distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+-- WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+-- License for the specific language governing permissions and limitations under
+-- the License.
+
+module Foreign.Ptr.CreateWithFinalizer (createWithFinalizer) where
+
+import Foreign
+  (FinalizerPtr, ForeignPtr, Ptr, Storable, addForeignPtrFinalizer,
+   mallocForeignPtr, withForeignPtr)
+
+createWithFinalizer ::
+  Storable a => (Ptr a -> IO ()) -> FinalizerPtr a -> IO (ForeignPtr a)
+createWithFinalizer initialize finalize = do
+  fp <- mallocForeignPtr
+  withForeignPtr fp initialize
+  addForeignPtrFinalizer finalize fp
+  return fp